Health officials warned that the high levels of fecal bacteria can cause problems for swimmers, including rashes, intestinal problems and respiratory infections. People should avoid contacting the water until the advisory is lifted.

"Whenever we find bacteria in the water it is a cause for concern," said Curtis Cude with the Oregon Health Authority, "especially for people who are vulnerable, people who might already be ill, people who have some sort of frail condition."

Children and elderly beachgoers might be especially at risk for problems. Visitors should also avoid water in nearby creeks.

Despite the concern, the Oregon Health Authority is not closing the beach. A spokesman said other recreational activity on the beach is safe. Neighboring beaches are also not affected.

State officials test water at recreational beaches several times during the spring and summer and say they usually find elevated bacteria levels a few times during that period.

This latest advisory could come down as soon as Thursday evening.

It’s not clear where the elevated levels of bacteria came from. Officials said it could be from sources in the ocean, or from sources on land such as storm runoff, sewer systems, septic systems, or human and animal waste.